1. Field of the Invention
The present invention relates to a hand-held pneumatic device worked by compressed air, and more specifically to a hog ring clamping device, such as a C ring clamping device.
2. Description of the Prior Art
A conventional C ring clamping device has a main body and a grip joined to a lower portion of the main body. The main body is provided with a pneumatic cylinder for turning jaws, and a push-button directional control valve. An air discharge passage connected to a discharge port of the directional control valve is formed in the grip so as to open at the lower portion of the grip. Another air discharge passage connected to another discharge port of the directional control valve is formed in the main body so as to open in a back portion of the main body.
Air discharged from the port of the pneumatic cylinder is discharged outside through the air discharge passage when the position of the directional control valve is changed and, therefore, the C ring clamping device generates large air discharge noise every time the directional control valve is operated to change the flow direction of air to deteriorate the working environment of a place where the C ring clamping device is used for clamping work using C rings.